• International Journal of Industrial Entomology and Biomaterials
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• v.42 no.1
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• pp.7-13
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• 2021

In the present study, the effect of heat treatment on the crystallinity of the outside of silkworm cocoon in nine different silkworm varieties was studied using ATR-FTIR spectroscopy. Additionally, the morphological structure and moisture regain of the cocoon were examined. The silkworm cocoon showed different colors and external features depending on the silkworm variety. Moreover, the thickness of the filament (15.3-27.6 ㎛) and moisture regain of the cocoon (9.0%-11.0%) were quite different depending on the silkworm variety. The crystallinity index of the cocoon outside varied from 52.1% to 56.1%, depending on the silkworm variety. J300 and MO42 showed the highest (56.1%) and the lowest (52.1%) crystallinity index, respectively, indicating that the microstructure of sericin of the outside of the cocoon was affected by the silkworm variety. Regardless of silkworm variety, their crystallinity indexes decreased from 52.1%-56.1% to 49.9%-43.6% depending on the silkworm variety by the heat treatment at 250 ℃. Interestingly, the crystallinity degree decrease was somewhat different depending on the silkworm variety, implying that the cocoon sericin microstructure is strongly influenced by the silkworm variety.

• International Journal of Industrial Entomology and Biomaterials
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• v.20 no.2
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• pp.115-116
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• 2010

The Eolrukmal and Hukpyobeom varieties were bred for special purpose such as experience and education. The Eolrukmal variety was selected and succeeded from the $F_1$ of Huka$\times$Galwon in 2004 summer. It has stripes and brown half-moon body marks. The Hukpyobeom variety was selected and succeeded from the $F_1$ of Remone$\times$Hukho in 2004 summer. It has black body color and bright yellow segments. They are healthy yellow cocoon spining varieties showing over 93% of high practical hatching ratio and 93.1% of emergence ratio. The Eolrukmal moth laid 450 egg/batch and the Hukpyobeom moth laid 440 egg/batch.

• International Journal of Industrial Entomology and Biomaterials
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• v.45 no.2
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• pp.126-130
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• 2022

The silkworm is a food material that can simultaneously ingest phytochemicals from mulberry leaves, proteins with essential amino acids, and fatty acids. They are known to have hypoglycemic properties; however, further functional investigation is needed. In this study, four varieties of 3^rd day of fifth instar silkworm with different cocoon colors, namely Baegokjam (BG), Goldensilk (GS), Yeonnokjam (YN), and Juhwangjam (JH), were compared in terms of antioxidant properties and cholesterol-lowering effect. JH, which had the highest polyphenol content (+38% vs. GS, p<0.05) showed high antioxidant efficacy. Treatment with JH also resulted in the lowest cholesterol biosynthesis enzyme activity (28% vs. control, p<0.05). In the animal study, high-fat diet (HFD)-fed mice that were orally administered JH extract for 12 weeks showed lower body weight gain (-10.4% vs. HFD, p<0.05) and serum total cholesterol levels (-12.7% vs. HFD, p<0.05). Comparing the varieties, JH had the highest effect. In future studies, analysis of the active ingredients according to their variety should be done.

• International Journal of Industrial Entomology and Biomaterials
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• v.27 no.2
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• pp.237-242
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• 2013

We investigated the 1-deoxynojirimycin (1-DNJ) content of extracts from silkworm larvae at each developmental stage within three silkworm varieties. We also compared the content of the following polyhydroxylated alkaloids in the silkworm extracts: 1-DNJ, fagomine, and 1,4-dideoxy-1,4-imino-d-arabinitol (DAB). In addition, we evaluated the glucose-lowering effects of silkworm extract powder in db/db mice. The 1-DNJ content was the highest in Yeonnokjam $5^{th}$ instar $3^{rd}$ d larvae and Hansaengjam $5^{th}$ instar $3^{rd}$ d larvae, which contained 18.4 mg/100 g dry weight and 18.3 mg/100 g dry weight, respectively. The $5^{th}$ instar $3^{rd}$ d larvae exhibited a higher content of 1-DNJ than that of $5^{th}$ instar $5^{th}$ d larvae among all varieties. The glucose-lowering effects of silkworm extracts and Yeonnokjam powder were tested on db/db mice, and the blood glucose levels were found to decrease significantly in the YR70 group. Silkworm extracts (180 mg/kg, 90 mg/kg, 45 mg/kg, and 22.5 mg/kg) and acarbose (50 mg/kg) were administered orally for 4 wk. Changes in water intake were not statistically significant between control and silkworm extract-treated groups. Compared to the control group, blood glucose levels in the silkworm extract powder-treated group decreased in the 22.5 mg/kg/d group after being administered for 4 wk. This decrease was statistically significant. Furthermore, biochemical changes in the AST(Aspartate aminotransferase), ALT(Alanine aminotransferase), TCHO(Total Cholesterol), TG(Triglyceride), LDL(Low density lipoprotein), and HDL(High density lipoprotein) levels in blood were not observed. However, statistically significant decreases in blood GLU in the 22.5 mg/kg/d group compared to that of the control group occurred. In addition, the epididymal fat weight of the silkworm extract powder-treated group decreased significantly in both the 22.5 mg/kg/d group and 180 mg/kg/d group compared to that of the control group, but there were no statistically significant changes in perirenal fat weight. These results demonstrate that silkworm extracts inhibit changes in blood glucose levels in model diabetic mice.

• Journal of Sericultural and Entomological Science
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• v.24 no.2
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• pp.73-80
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• 1983

1. The varietal difference in amylase activity of the digestive fluid of the 5th instar larvae reared on the artificial diet was investigated, using the parent commercial silkworm varieties of Japanese strain. The amylase activity was large different among silkworm varieties. The activity was strong in Hansaeng-1, Jam 115 and Jam 117, medium in Hansaeng-3, Jam 113, Jam 119, and Jam 201, weak in Jam 107, Jam 121 and Gyeongchu. The amylase of the digestive fluid of ten parent commercial silkworm varieties is possible-(ae) type, compared with ＋(＋$\^$ae/) type of Daizo. 2. To investigate the effect of a-amylase pre-treatment of the artificial diet, larvae were fed with the diet treated by a-amylase during 4th-5th instar periods. The blood sugar content and cocoon qualities were slightly higher in the experimental larvae than those in the control, while showing the slight less body weight, amylase activity and dietary efficient.

• Journal of Sericultural and Entomological Science
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• v.20 no.2
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• pp.32-35
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• 1978

The infectious flacherie viruses are serious diseases in the silkworm, which affects the cocoon crops. However, there is only a few study on this diseases up-to-date in Korea and, in this experiment, the authors investigated the resistance of the silkworm varieties to flacherie and Ina-flacherie viruses by peroral infection. A cross, Hansaeng ＃1$\times$ Harisaeng ＃2, showed the highest resistance to the flacherie virus a Mudeung$\times$Geumho showed the lowest resistance among the examined varieties. It seemed that the varietal difference of resistance against Ina-flacherie virus was appeared and Jam117$\times$ Jam118, Gyeongchu$\times$Yeonil, Mudeung$\times$Geumho, Hansaeng＃1$\times$Hansaeng＃2 and Hansaeng＃3 $\times$ Hansaeng ＃4 showed non susceptibility by peroral infection. However it was shown that Jam115 $\times$Jam116 had the lowest resistance to Ina-flacherie virus.

• Journal of Life Science
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• v.32 no.12
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• pp.947-955
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• 2022

Silkworms, which have recently shown promise as functional health foods, show functional differences between varieties; therefore, the need for variety identification is emerging. In this study, we analyzed the whole silkworm genome to identify 10 unique silkworm varieties (Baekhwang, Baekok, Daebaek, Daebak, Daehwang, Goldensilk, Hansaeng, Joohwang, Kumkang, and Kumok) using single nucleotide polymorphisms (SNP) present in the genome as biomarkers. In addition, nine SNPs were selected to discriminate between varieties by selecting SNPs specific to each variety. We subsequently created a decision tree capable of cross-verifying each variety and classifying the varieties through sequential analysis. Restriction fragment length polymorphism (RFLP) was used for SNP867 and SNP9183 to differentiate between the varieties of Daehwang and Goldensilk and between Kumkang and Daebak, respectively. A tetra-primer amplification refractory (T-ARMS) mutation was used to analyze the remaining SNPs. As a result, we could isolate the same group or select an individual variety using the nine unique SNPs from SNP780 to SNP9183. Furthermore, nucleotide sequence analysis for the region confirmed that the alleles were identical. In conclusion, our results show that combining SNP analysis of the whole silkworm genome with the decision tree is of high value as a discriminative marker for classifying silkworm varieties.

• International Journal of Industrial Entomology and Biomaterials
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• v.31 no.2
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• pp.56-61
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• 2015

Rutin is an important bioflavonoid that is consumed in the daily diet. This study compared the functional components of rutin from various silkworm species using a gene database with those of rutin produced by silkworms selectively bred through cross-combinations. We made comparisons between the geographical origin and species of silkworm using a gene database and discovered that rutin activity was ranked in the following order by species, Chinese (C5)> miscellaneous varieties (Jamsaeng 1 Ho) >Japanese (Jam 115) > European (E58) >Korean (Sun 3 ho). However, rutin levels with respect to various genetic traits (blood color, silk color, and egg color) were consistent. In order to study rutin changes that occurred during the cross breeding of the silkworm gene, we bred cross-combinations utilizing Jam 115 and the 4051 silkworms. In conclusion, in order to provide information about the constituents of functional materials contained in silkworm powder, it is imperative that silkworm cross breeding occurs so that the database of functional materials extracted from silkworms will expand.

• Journal of Sericultural and Entomological Science
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• v.26 no.1
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• pp.35-51
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• 1984

In order to know the similarity of the electrophoretic protein patterns, distributional aspects of the frequency in each protein band, differences of protein patterns between female and male, and the number of the total protein bands of each variety in the haemolymph of the silkworm pupae according to their geographical origin, the silkworm varieties, and both the sexes, variable electrophoretic protein patterns were observed by polyacrylamide gel electrophoresis, using the silkworm strains which have been reared in the sericultural experiment station. 1. The total number of electrophoretic protein bands classified were twenty-eight, and nearly fourteen bands were shown by each variety on an average. 2. According to their geographical origin, the mean values of the similarity were 20.0%, 28.3% and 14.3% in Japanese, Chinese and European respectively, and the highest similarity was observed between Chinese varieties. 3. The similarity of 129 varieties were tested and it was 22.5%, 23.5% in female and male respectively. 4. The electrophoretic protein patterns in 129 varieties were tested and variation was found in 109 patterns in female and 112 in male. 5. The frequency of the each specified protein band in female and male having variation in protein bands in each variety was found averagely 6.6%. 6. The distribution frequency of the classified 28 protein bands in both the sexes within each geographical origin was variable from 0% to 100%. 7. Among the classified 28 protein bands, HP 11 protein band was found common in all the varieties tested. 8. HP 3 and HP 4 protein bands in female showed high density in electropherograms than in male.

• Journal of Sericultural and Entomological Science
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• v.21 no.1
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• pp.46-49
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• 1979

These experiments were made in order to compare the productivity of various varieties of F$_1$silkworm eggs imported from foreign sericultural countries with the productivity of some F$_1$silkworm eggs varieties produced by Turkey. The results are summarized as follows: 1. In the durations of whole instar, it lasted 30∼38 days under natural rearing conditions but Jam 107${\times}$Jam 105 about 30 days. 2. Cocoon yield per case of silkworm eggs was shown significantly among the varieties. Thaiei ${\times}$ Choan was the highest yield of cocoon, followed by Isonzo, Piave, M-198, M${\times}$N, S${\times}$P, J${\times}$C and Jam 107${\times}$Jam 108 in that order. 3. In the percentage of cocoon shell, M-197 was the highest and other varieties were almost on the same level of cocoon shell, but Jam 107${\times}$ Jam 108 was the lowest percentage. 4. In the weight of a cocoon, Choan${\times}$Thaiei was the heaviest, followed by S${\times}$P, C${\times}$J, M${\times}$N, M-197, Piave, Livenzo and Jam 107${\times}$Jam 108 in that order. 5. In the raw silk percentage of fresh cocoon, Choan${\times}$Thaiei, 3 Italian varieties and Turkish M${\times}$N. C${\times}$J belonged to the first group of better raw silk percentage, followed Polish M-197 and Jam 107${\times}$1am 108 in that order.